By far, most commercial LANs are based on the Ethernet LAN specification. Ethernet LANs typically come in two speeds, 10 megabits per second, and increasingly 100 megabits per second (so-called "Fast Ethernet").
Token ring is also a major LAN specification standard, though it trails Ethernet by an extremely wide margin. Typically, only the "bluest" of corporations, that is, corporations with a strict allegiance to IBM, still use Token Ring^[1].

Standard
Data Rate 
Modulation Scheme
Security
Pros/Cons & More Info
IEEE 802.11	

(Wi-Fi) Up to 54Mbps in the 5GHz band OFDM WEP & WPA Products that adhere to this standard are considered "Wi-Fi Certified." Eight available channels.
Less potential for RF interference than 802.11b and 802.11g. Better than 802.11b at supporting multimedia voice, video and large-image applications in densely populated user environments. Relatively shorter range than 802.11b. Not interoperable with 802.11b.

(Wi-Fi) Up to 11Mbps in the 2.4GHz band DSSS with CCK WEP & WPA Products that adhere to this standard are considered Wi-Fi Certified. Not interoperable with 802.11a. Requires fewer access points than 802.11a for coverage of large areas. Offers high-speed access to data at up to 300 feet from base station. 14 channels available in the 2.4GHz band (only 11 of which can be used in the U.S. due to FCC regulations) with only three non-overlapping channels.

(Wi-Fi) Up to 54Mbps in the 2.4GHz band OFDM above 20Mbps, DSSS with CCK below 20Mbps WEP & WPA Products that adhere to this standard are considered "Wi-Fi Certified." May replace 802.11b. Improved security enhancements over 802.11. Compatible with 802.11b. 14 channels available in the 2.4GHz band (only 11 of which can be used in the U.S. due to FCC regulations) with only three non-overlapping channels.

(WiMAX) Specifies WiMAX in the 10 to 66 GHz range OFDM DES3 and AES Commonly referred to as WiMAX or less commonly as Wireless MAN or the Air Interface Standard, IEEE 802.16 is a specification for fixed broadband wireless metropolitan access networks (MANs)

(WiMAX) Added support for the 2 to 11 GHz range.
OFDM DES3 and AES Commonly referred to as WiMAX or less commonly as WirelessMAN or the Air Interface Standard, IEEE 802.16 is a specification for fixed broadband wireless metropolitan access networks (MANs)
Bluetooth: Up to 2Mbps in the 2.45GHz band FHSS PPTP, SSL or VPN No native support for IP, so it does not support TCP/IP and wireless LAN applications well. Not originally created to support wireless LANs. Best suited for connecting PDAs, cell phones and PCs in short intervals.
HomeRF: Up to 10Mbps in the 2.4GHZ band FHSS Independent network IP addresses for each network. Data is sent with a 56-bit encryption algorithm. Note: HomeRF is no longer being supported by any vendors or working groups. Intended for use in homes, not enterprises. Range is only 150 feet from base station. Relatively inexpensive to set up and maintain. Voice quality is always good because it continuously reserves a chunk of bandwidth for voice services. Responds well to interference because of frequency-hopping modulation.
HiperLAN/1 (Europe): Up to 20Mbps in the 5GHz band CSMA/CA Per-session encryption and individual authentication. Only in Europe. HiperLAN is totally ad-hoc, requiring no configuration and no central controller. Doesn't provide real isochronous services. Relatively expensive to operate and maintain. No guarantee of bandwidth.
HiperLAN/2 (Europe): Up to 54Mbps in the 5GHz band OFDM Strong security features with support for individual authentication and per-session encryption keys. Only in Europe. Designed to carry ATM cells, IP packets, Firewire packets (IEEE 1394) and digital voice (from cellular phones). Better quality of service than HiperLAN/1 and guarantees bandwidth.
OpenAir: Pre-802.11 protocol, using Frequency Hopping and 0.8 and 1.6 Mb/s bit rate CSMA/CA with MAC retransmissions OpenAir doesn't implement any encryption at the MAC layer, but generates Network ID based on a password (Security ID) OpenAir is the proprietary protocol from Proxim. All OpenAir products are based on Proxim's module.

[1] Token Ring:A type of computer network in which all the computers are schematically arranged in a circle.